The present invention relates to a means for sealing containers at high speed with closure caps. More particularly, it relates to improvements in a method and means for moving hollow thin-walled relatively flexible containers through a straight line sealing machine and for applying and sealing closure caps onto the moving containers.
The high speed sealing of containers by a method which uses a straight line sealing machine is well known. In these machines, the filled containers are carried along in a straight line beneath a cap applying means which lightly places a closure cap on each moving container top. Thereafter, the jars are moved beneath a sealing means which tightly seals the closure cap to the moving containers. Prior methods and machines of this general type have been used with relatively rigid glass or other containers and they have applied the closure caps with either a press on motion, or alternatively, a rotary motion such as by applying a threaded closure to a threaded container top.
The improvements of the present means provide for the high speed sealing of relatively thin-walled and flexible containers. In normal sealing machinery such containers would be distorted by the sealing mechanism thereby causing the sealed container to be discharged with permanently distorted walls or with unacceptable variations in the sealed package, particularly for vacuum sealed containers.
Additionally, the method and means of the present invention provides for a high speed sealing of thin-walled containers by applying the closure caps with a significant press on motion of the closure cap downwardly over the container threads or lugs plus a final and limited rotary or twisting movement of the closure caps. This composite sealing movement, as well as the use of tamper evident composite closures having container gripping bands, has been facilitated by a combination of a closure softening means in the cap applying mechanism.
Accordingly, as object of the present invention is to provide an improved straight line method and means for sealing containers.
Another object of the present invention is to provide an improved straight line method and means for sealing thin-walled containers.
Another object of the present invention is to provide an improved container gripping method and means for a straight line container sealing machine.
Another object of the present invention is to provide an improved composite motion sealing means for closure caps.
Another object of the present invention is to provide an improved combination of means for heat softening and sealing composite plastic and metal closure caps.
Other and further objects of the present invention will become apparent upon an undestanding of the illustrative embodiments about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.